Again - and I don't want to seem too positive here - I don't see how this changes things all that much. Perhaps as it evolves, but for now ...
People are concerned that this excludes the families with toddlers, for whom a later return is tricky. But under the unlimited standby system, didn't it still mean a rush to RD, or face an unbearable wait, WITH a toddler? How is that better?
With the Epcot M&G there was the mad dash and six hour waits in line. You got there too late and you were out of luck. This has got to be an improvement. Dedicated A&E fans are more likely in any scenario to get through - either by showing up early for a Standby pass, or waiting in line half the day, or coming back late when the crowds have thinned, etc.
When you have a tremendously popular attraction, especially one with extremely limited throughput, there will always be those unable to get in. I guess I just give Disney credit for trying to address being trapped in a brutal line half the day. There are other solutions, of course - like expanding capacity - but that's another discussion ...
This is why Disney should add the sisters to Akershus in addition to making this change. They could make it a signature and charge more money and burn more dining credits.
It also creates an alternative avenue for access. Making only these changes to availability is a mistake. If they're going to do this, and it seems they are, then they need to add alternate access.